Various synthetic rubbers made from alkadiene monomers and from monovinyl arenes are known in the art. Among these polymers are thermoplastic elastomers that are non-cured, olefinically hydrogenated copolymers of the monomers just described, such as polystyrene/hydrogenated polybutadiene/ polystyrene. The thermoplastic elastomers can be readily formed into useful articles which exhibit desirable tensile strength and elongation without curing. However, it would be desirable to have novel thermoplastic elastomers available that exhibit high tensile strength and elongation. Furthermore, it would be desirable to have such thermoplastic elastomers available which have broad temperature ranges in which they soften and finally become sufficiently fluid that they can be readily used in various fabrication procedures.